NASA clearedthe space shuttle Atlantis for its planned Monday launch to the Hubble SpaceTelescope, a long-delayed mission aimed at extending the iconic observatory?slifespan.

Missionmanagers here at NASA?s Kennedy Space Center held one last review Saturday thatfound Atlantis and its crew of seven astronauts fit to fly for the fifth and finalmission to overhaul Hubble. The mission is poised to rocket spacewardMonday at 2:01 p.m. EDT (1801 GMT).

?Atlantishas been on the ground for awhile, so that team is reallyanxious to fly,? said NASA?s shuttle launch director Mike Leinbach. ?Andhopefully we?ll do that Monday.?

The shuttlehas an 80 percent chance of good weather on launch day, with thick clouds and athe potential for rain at an emergency landing strip in Spain posing the onlythreats to liftoff, NASA officials said.

Leinbachsaid a second space shuttle, the Endeavour orbiter, is also primed atop its ownlaunch pad toflya rescue mission just in case Atlantis is damaged beyond repair during theflight. Atlantis astronauts won?t be able to seek refuge aboard theInternational Space Station because of Hubble?s different orbit and altitude.Hubble flies about 350 miles (563 km) above Earth and in a different orbit thanthe 220-mile (354-km) high space station.

NASA hasprepared Endeavour to fly with a few days to a week of a declared emergency, butofficials have said it the likelihood of needing the rescue mission isextremely remote.

Meanwhile,Altman and his crew have a full mission ahead of them. The astronauts plan to performa five-spacewalk marathon that will install two new cameras aboard Hubbleand attempt repairs on instruments that were never designed to be fixed inspace. If all goes well, the mission should extend Hubble?s life through atleast 2014.

NASA has three tries tolaunch Atlantis before standing down for a previously scheduled militaryoperation at the nearby Cape Canaveral Air Force Base. If the shuttle does notlaunch by May 13, NASA would aim for a May 22 launch to wait out the military?sactivity and recharge new batteries bound for Hubble.